1. Technical Field
The present invention relates to a communication apparatus and a method of controlling the communication apparatus.
2. Related Art
A LAN board functioning as a node of a LAN (Local Area Network) by attaching to an information device has to monitor the flow of packet data on the LAN all the time. Therefore, the LAN board has to be operated by receiving power supply at a constant level all the time such that power supply to an entire internal circuit is not cut off.
In order to reduce power consumption of an information device equipped with such LAN board, there is a following technique disclosed in JP-A-2003-108273. In the technique disclosed in JP-A-2003-108273, after a predetermined period of time has passed in a stand-by state, the LAN board transitions to an operation stand-by state with a power-saving operation mode. Then, if the LAN board detects a packet addressed thereto on a LAN, or if the LAN board detects a packet to be transmitted to the information device, the LAN board returns to an operation stand-by state which is not the power-saving operation mode but a normal operation mode. At the same time, the LAN board makes the information device be in an operation stand-by state with a normal operation mode, and then, transmits the packet to the information device.
However, depending on information contents included in a packet, even when the packet is does not need to be transmitted to the information device immediately, the information device also returns to the operation stand-by state with the normal operation mode together with the LAN board. Therefore, power consumption of the information device equipped with the LAN board cannot be effectively reduced.